This invention relates to improvements in spiral separators used for mineral separation.
A conventional spiral separator for mineral separation has a pair of spirals, or helical sluices, mounted coaxially about a vertical central column, a pulp of water and the minerals to be separated being fed into the upper ends of the spirals to flow down them and form bands or strata containing minerals of different density characteristics, splitter blades mounted at intervals in each spiral dividing the strata, and take-off openings, normally circular, carrying off the material to one side of the splitter blade.
The characteristics of different types of pulp may, however, vary considerably, and the location of take-offs which may be satisfactory for one mineral separation operation may be quite unsatisfactory for another.
It is uneconomical to provide a range of spiral concentrators with take-offs located differently, or to reposition the take-offs of an existing mineral separation apparatus, and it is well known to attempt to compensate for flow variations of different kinds of pulp by angular adjustment of the splitter blades. This, however, is not fully satisfactory as a splitter blade, to achieve good results, should be directed into the flow of the pulp, and not across it. When a splitter blade is turned either inwards or outwards, with respect to the spiral, with the object of taking off the desired proportion of pulp into concentrate, the continuity of the flow of the pulp is adversely affected and sand barring of the pulp takes place in the spiral.